Vetter (out of business) casement sliding hinge track.

My 25 yr old Vetter wood casement window has a broken hinge slide. The 1 lunch black plastic-coated clip that slides in the casing-mounted track is broken and will not stay in the track. The first picture shows the good (left) & bad (right) parts. The window-mounted bracket that it is a part of is 7.5 in long with a 5.5 in attached arm. I have multiple windows that have the same problem to a lesser degree and would be interested in multiple brackets depending on price and availability, however this is the only one that is broken to the point of not staying in the track at all. Please advise, Ken.